Published: December 20, 2013

BANGUI, Central African Republic — Clashes broke out in several quarters on Friday here in the capital, leaving 19 people dead, shattering the tentative lull that had held for a week and revealing the dangerous numbers of armed militiamen still in the city.

Rebecca Blackwell/Associated Press

Residents of Bangui walk past a body of a man lying at a checkpoint guarded by African Union peacekeepers on Friday.

French and African Union peacekeeping troops turned out in force, increasing patrols in different parts of the city on Friday afternoon in an effort to contain the violence as hospitals reported a sharp increase in civilian casualties.

The city’s main hospital received 54 wounded and three dead, according to Martin Searle, a spokesman for the international organization Doctors Without Borders, which has a team working in the hospital. Teams of the Central African and the International Red Cross found 19 dead and 35 wounded during the day, said Georgios Georgantas, the head of the International Committee of the Red Cross in Bangui.

Day by day townspeople had been gaining confidence, opening stores and street stalls. Yet in a sign of how tense the situation remains after about 600 people were killed in massacres two weeks ago, extended bursts of machine-gun fire sent people scurrying home. By midday the city appeared deserted except for peacekeepers and foreign relief workers driving through the streets.

The deterioration began Thursday evening when Chadian troops, part of the peacekeeping force put in place by the United Nations, clashed with gunmen and took several casualties. Early Friday morning, gunmen burst into a Muslim neighborhood at dawn, killing two people and wounding several others as they fled in panic, according to residents.

Elsewhere in the city, African Union peacekeepers came under fire by militia members at midmorning and fired back, killing the gunmen and destroying their vehicle. The gunfire resounded loudly in the center of town.

As people fled, groups of peacekeepers traveled toward the trouble spots. Ambulances ferried wounded civilians to the hospitals. Doctors in the main hospital said most of the casualties involved people who were shot as they fled the gunfire. Muslims and Christians lay on the floor and benches of the first aid post in the central hospital.

They described a dawn attack by militia fighters wearing uniforms and carrying automatic weapons, rockets and grenades in the mainly Muslim neighborhood called Kilometer 5 on the west side of town.

“At 5 a.m. we heard firing, and at 7 a.m. they entered the neighborhood,” said one resident, Abdul Karim, 19, who received a flesh wound in the leg. “Everyone started to flee, and they fired at us, Muslims and Christians. It did not matter what we were.”

A 19-year-old lay on his mother’s lap, shot in the back. Two cousins sat on a bench, one nursing a bullet wound in his arm. They were all Muslims, and they said their attackers were a combination of the mainly Christian anti-balaka self-defense forces and more experienced former army soldiers loyal to the former government of François Bozizé, the ousted president.

If those accounts are confirmed, they are an indication that the anti-balaka militia have much better weapons than the machetes, knives and old rifles they are often reported to have. The attack on the Muslim neighborhood will almost certainly invite retaliation from the mainly Muslim Seleka rebels who carried out most of the mass killings in the past two weeks.

Another group of wounded consisted of street sellers and shoppers caught in crossfire when peacekeeping troops came under fire from a group of militiamen at midmorning. Witnesses blamed Seleka gunmen, saying they opened fire on the African Union troops.

One wounded man named Wandika, 27, lay on the floor with a bullet wound to the thigh. His friend Auguste sat beside him. They gave only their first names because of the growing tensions. Wandika said that he made a living selling wood and that Friday was the first day he had dared to come out to try to make some money since the massacres.

“This was the first day that I tried to sell something,” he said. “I have not sold anything since all this happened.”

The sharp rise in casualties has alarmed aid groups working in the Central African Republic because it was a sharp reversal in the steady improvements since the deployment of 1,600 French troops two weeks ago. Since the French started disarming militias, “we have been receiving fewer and fewer people wounded by gunshots, but today we saw a big increase,” Mr. Searle said.

The French sent extra forces into the city on Friday after the clash involving Chadian peacekeeping forces, yet seemed unaware of the large number of civilian casualties that occurred during the day.

“French forces deployed into the city to have a robust presence after the events of Thursday night, and by the end of the night it was quiet,” said Lt. Col. Thomas Mollard, a spokesman for the French force. Friday was uneventful for the French forces, he said. “There were no major incidents for our forces, and we see the situation going forward.”

Troops of the Eighth Parachute Regiment of the Marine Infantry patrolled Friday night through the northeast neighborhoods where the Chadian troops had come under attack the day before. Units in armored vehicles posted watch as troops patrolled on foot through the hills above the city.

The anti-balaka militias are widely known to be positioned behind the hills to the north and west of Bangui. They infiltrate the city through the mostly Christian neighborhoods that are sympathetic to them. Several anti-balaka fighters, bearing knives and machetes, stood watch as the French maneuvered their vehicles up the narrow rutted dirt tracks through the hillside communities.

Part of the mission of the French troops is to disarm the various militias as they encounter them and prevent any attacks on civilians. But they said they would not disarm people bearing machetes because a machete was as much a tool as a weapon. “Here the machete is like a penknife at home,” said Alban, the adjutant in command of the unit. According to French military rules, he gave only his first name.

“They hide the bigger weapons as any unit would,” he added. “That’s why we have a patrol going in farther north.” The patrol had no contacts, but the French seem to be counting on persistent patrolling to reduce tensions and contain the militias. “We talk to the people and try to calm their spirits,” Alban said. “But it is two clans who are facing off against each other, and there is not much we can do about that.”